1. Technical Field
The present invention generally relates to bicycles and, more particularly, to bicycles that are convertible between different riding configurations. Specifically, the present invention relates to a bicycle that can be quickly and easily configured in an upright position, a recumbent position, and a tandem position.
2. Background Information
A bicycle is a two-wheeled vehicle that is propelled by energy supplied by the rider. The most traditional form of a bicycle includes a chain and sprocket drive mechanism wherein a small sprocket is attached to the rear wheel and a large sprocket is attached to a crank mechanism that allows the user to provide energy to the bicycle through his legs. The bicycle typically has two wheels of equal size. A steering mechanism allows the front wheel to be turned relative to the rear wheel to allow the bicycle to be guided through turns. The traditional upright bicycle locates the pedals generally below the seat of the rider such that the rider""s weight shifts from one foot to the other during forward propulsion. One problem with this type of bicycle is that the rider""s center of gravity is positioned above the majority of the bicycle frame.
In general, a longer wheel base and a lower center of gravity provides greater stability. A recumbent bicycle is generally longer than a conventional upright bicycle and positions the rider in a lower position to the ground. The rider is generally sitting in a slightly reclined position while riding a recumbent bicycle. Recumbent bicycles provide increased comfort, greater pedal efficiency, and a lower center of gravity compared to the conventional upright bicycle.
Tandem bicycles are also known in the art. A tandem bicycle allows two riders to power a single bicycle unit that typically has a pair of crank mechanisms driving a single wheel or a pair of crank mechanisms driving individual wheels.
The art generally desires a bicycle configuration that allows the user to selectively configure his bicycle between the upright, recumbent, and tandem positions so that the user may enjoy the benefits of all three types of bicycle configurations while only purchasing a single bicycle. Although some prior art devices provide a conversion function, the devices either require the greasy chain to be manually moved between sprockets, position the seat too high, or require relatively complicated pivoting arrangements to move the elements of the bike between the different positions. The art desires the conversion to be simple and clean so that the user will not hesitate to make the conversion when desired.
One type of conversion configuration for a bicycle is disclosed in U.S. Pat. No. 5,951,034. The conversion apparatus disclosed in this patent is functional but includes some undesirable drawbacks. U.S. Pat. No. 5,620,196 allows a recumbent bicycle to be connected with other recumbent bicycles (FIG. 6) so that a tandem bicycle may be created. U.S. Pat. No. 5,419,574 discloses a bicycle frame that allows the crank to be positioned in a variety of different positions. U.S. Pat. No. 4,502,705 discloses a semirecumbent tandem bicycle but includes a relatively complicated chain drive that is used by the front rider. U.S. Pat. No. 4,248,448 discloses a bicycle that allows the user to sit in an upright position or lie forward in a prone riding position. German document DE 3837-018-A discloses a bicycle having an adjustable riding position that includes a seat and pedal arrangement on a hinged frame configuration that allows the seat to pivot rearwardly and downwardly while pivoting the crank mechanism upwardly. Each of the bicycle configurations noted above has at least one undesirable aspect and room for improvement remains in the art.
In view of the foregoing, the present invention provides a bicycle that may be selectively configured in one of an upright, recumbent, or tandem position. The invention provides a bicycle that may be selectively configured without requiring the user to move the chain of the drive mechanism. The bicycle of the present invention achieves this objective by providing gear boxes in the drive mechanism of the bicycle. When the bicycle is converted from the upright to the recumbent position, a drive shaft is placed between a front gear box and the rear gear box to allow the user to drive the rear drive mechanism with a front crank assembly.
The invention also provides a frame configuration that uses quick-disconnect locking clips to hold the frame together in its different configurations.
The bicycle also provides a configuration that positions the rider""s seat below the top of the rear wheel in the recumbent position so that the recumbent bicycle is easy to ride.